RT-22 CrAO – H2O maser sources patrolling

2019 ◽  
Vol 2 (1) ◽  
pp. 13-21
Author(s):  
L. N. Volvach ◽  
◽  
A. E. Volvach ◽  
M. G. Larionov ◽  
A. I. Dmitrotsa ◽  
...  
Keyword(s):  
Maser Sources

SiO Maser Sources toward the Sagittarius B2 Molecular Cloud

1997 ◽  
Vol 478 (1) ◽  
pp. 206-210 ◽  
Author(s):  
Shigetomo Shiki ◽  
Masatoshi Ohishi ◽  
Shuji Deguchi
Keyword(s):  
Molecular Cloud ◽  
Maser Sources

Near infrared photometry of stellar maser sources

1986 ◽  
Vol 10 (1) ◽  
pp. 62-66 ◽  
Author(s):  
Ke-ping Zhou ◽  
Yun-xiang Hao ◽  
Pei-sheng Chen ◽  
Yun Zhang ◽  
Heng Gao
Keyword(s):  
Near Infrared ◽  
Infrared Photometry ◽  
Maser Sources

scholarly journals Snapshot VLBI Observations of SiOv=1 andv=2 (J=1-0) Maser Sources

2001 ◽  
Vol 53 (2) ◽  
pp. 259-273 ◽  
Author(s):  
Hiroshi Imai ◽  
Makoto Miyoshi ◽  
Nobuharu Ukita ◽  
Masaki Morimoto ◽  
Takahiro Iwata ◽  
...  
Keyword(s):  
Vlbi Observations ◽  
Maser Sources

scholarly journals Millimetre wavelength methanol masers survey towards massive star forming regions

2007 ◽  
Vol 3 (S242) ◽  
pp. 234-235
Author(s):  
T. Umemoto ◽  
N. Mochizuki ◽  
K. M. Shibata ◽  
D.-G. Roh ◽  
H.-S. Chung
Keyword(s):  
Detection Rate ◽  
Massive Star ◽  
Molecular Line ◽  
Maser Emission ◽  
Star Forming ◽  
Methanol Maser ◽  
Physical Conditions ◽  
Star Forming Regions ◽  
Methanol Masers ◽  
Maser Sources

AbstractWe present the results of a mm wavelength methanol maser survey towards massive star forming regions. We have carried out Class II methanol maser observations at 86.6 GHz, 86.9 GHz and 107.0 GHz, simultaneously, using the Nobeyama 45 m telescope. We selected 108 6.7 GHz methanol maser sources with declinations above −25 degrees and fluxes above 20 Jy. The detection limit of maser observations was ~3 Jy. Of the 93 sources surveyed so far, we detected methanol emission in 25 sources (27%) and “maser” emission in nine sources (10%), of which thre “maser” sources are new detections. The detection rate for maser emission is about half that of a survey of the southern sky (Caswell et al. 2000). There is a correlation between the maser flux of 107 GHz and 6.7 GHz/12 GHz emission, but no correlation with the “thermal” (non maser) emission. From results of other molecular line observations, we found that the sources with methanol emission show higher gas temperatures and twice the detection rate of SiO emission. This may suggest that dust evaporation and destruction by shock are responsible for the high abundance of methanol molecules, one of the required physical conditions for maser emission.

scholarly journals Hot and cold running water: understanding evolved star winds

2017 ◽  
Vol 13 (S336) ◽  
pp. 347-350
Author(s):  
A. M. S. Richards ◽  
M. D. Gray ◽  
A. Baudry ◽  
E. M. L. Humphreys ◽  
S. Etoka ◽  
...  
Keyword(s):  
Mass Loss ◽  
Circumstellar Envelope ◽  
Number Density ◽  
Running Water ◽  
Physical Conditions ◽  
Evolved Stars ◽  
Order Of Magnitude ◽  
Homogeneous Regions ◽  
Maser Sources

AbstractOutstanding problems concerning mass-loss from evolved stars include initial wind acceleration and what determines the clumping scale. Reconstructing physical conditions from maser data has been highly uncertain due to the exponential amplification. ALMA and e-MERLIN now provide image cubes for five H2O maser transitions around VY CMa, at spatial resolutions comparable to the size of individual clouds or better, covering excitation states from 204 to 2360 K. We use the model of Gray et al. 2016, to constrain variations of number density and temperature on scales of a few au, an order of magnitude finer than is possible with thermal lines, comparable to individual cloud sizes or locally almost homogeneous regions. We compare results with the models of Decin et al. 2006 and Matsuura et al. 2014 for the circumstellar envelope of VY CMa; in later work this will be extended to other maser sources.

scholarly journals Intermittent maser flare around the high-mass young stellar object G353.273+0.641

2012 ◽  
Vol 8 (S287) ◽  
pp. 98-102
Author(s):  
Kazuhito Motogi ◽  
Kazuo Sorai ◽  
Kenta Fujisawa ◽  
Koichiro Sugiyama ◽  
Mareki Honma
Keyword(s):  
Light Curve ◽  
Small Area ◽  
Linear Acceleration ◽  
High Mass ◽  
Velocity Range ◽  
Time Resolved ◽  
Almost All ◽  
Maser Sources ◽  
Water Maser

AbstractThe water maser site associated with G353.273+0.641 is classified as a dominant blueshifted H2O maser, which shows an extremely wide velocity range (± 100 km s−1) with almost all flux concentrated in the highly blueshifted emission. The previous study has proposed that this peculiar H2O maser site is excited by a pole-on jet from high mass protostellar object. We report on the monitoring of 22-GHz H2O maser emission from G353.273+0.641 with the VLBI Exploration of Radio Astrometry (VERA) and the Tomakamai 11-m radio telescope. Our VLBI imaging has shown that all maser features are distributed within a very small area of 200 × 200 au2, in spite of the wide velocity range (> 100 km s−1). The light curve obtained by weekly single-dish monitoring shows notably intermittent variation. We have detected three maser flares during three years. Frequent VLBI monitoring has revealed that these flare activities have been accompanied by a significant change of the maser alignments. We have also detected synchronized linear acceleration (−5 km s−1yr−1) of two isolated velocity components, suggesting a lower-limit momentum rate of 10−3 M⊙ km s−1yr−1 for the maser acceleration. All our results support the previously proposed pole-on jet scenario, and finally, a radio jet itself has been detected in our follow-up ATCA observation. If highly intermittent maser flares directly reflect episodic jet-launchings, G353.273+0.641 and similar dominant blueshifted water maser sources can be suitable targets for a time-resolved study of high mass protostellar jet.

scholarly journals The detection of new methanol masers in the 5−1 — 40E Line

2002 ◽  
Vol 206 ◽  
pp. 195-198
Author(s):  
Sergei V. Kalenskii ◽  
Vyacheslav I. Slysh ◽  
Irina E. Val'tts ◽  
Anders Winnberg ◽  
Lars E. B. Johansson
Keyword(s):  
Velocity Field ◽  
Frequency Analysis ◽  
Linear Polarization ◽  
Class I ◽  
Narrow Line ◽  
Bipolar Outflow ◽  
Compact Class ◽  
Extended Sources ◽  
Methanol Masers ◽  
Maser Sources

Fifty-one objects in the 5−1 − 40E methanol line at 84.5 GHz was detected during a survey of Class I maser sources. Narrow maser features were found in 17 of these. Broad quasi-thermal lines were detected towards other sources. One of the objects with narrow features, the young bipolar outflow L 1157 was also observed in the 80 − 71A+ line at 95.2 GHz; a narrow line was detected at this frequency. Analysis showed that the broad lines are usually inverted. The quasi-thermal profiles imply that the line opacities are not larger than several units. These results confirm the plausibility of models in which compact Class I masers appear in extended sources as a result of an appropriate velocity field.Measurements of linear polarization at 84.5 GHz in 13 sources were made. No polarization was found except a tentative detection of a weak polarization in M 8E.

VERA Single Dish Observations

2017 ◽  
Vol 13 (S336) ◽  
pp. 307-308
Author(s):  
Kazuyoshi Sunada ◽  
Takumi Nagayama ◽  
Aya Yamauchi ◽  
Tomoya Hirota ◽  
Katsunori M. Shibata ◽  
...  
Keyword(s):  
Maser Sources ◽  
Bright Source ◽  
Water Maser

AbstractWe will report the activities of the VERA single-dish observations. We are carrying out single-dish observations with two purposes. The first purpose is the monitoring of known H2O maser sources. At present, we are carrying out monitoring observations for 312 H2O maser sources at intervals of two months. The second purpose is the search for new water maser sources. We selected 901 target sources from the AKARI FIS Bright Source Catalogue. We found 61 new H2O maser sources.

Sign in / Sign up

Export Citation Format

Share Document